Abstract P1-01-05: Clinical Significance of Tumor Burden in the Sentinel Nodes after Neoadjuvant Therapy Differs from Sentinel Nodes in the Adjuvant Setting and This May Influence the Management of the Axilla

Abstract

Abstract Background. Lymph node metastases are the most significant prognostic factor for breast cancer patients. The use of sentinel node biopsy (SLN) has generated an increased detection of positive nodes through the identification of isolated tumor cells (ITC) and micrometastasis. The objective of this study is to evaluate the significance of SLN micrometastasis and ITC for patients undergoing neoadjuvant chemotherapy versus patients undergoing surgery first. Material and Methods. A total of 571 patients with clinically node negative T1-T3 breast cancer underwent SLN surgery from 2004 to 2008. Clinicopathological data were reviewed and comparison was made between results in the adjuvant and neoadjuvant setting. Results. Of the 571 patients, 71 patients (12.5%) underwent SLN biopsy after neoadjuvant chemotherapy and 500 (87.5%) underwent surgery first. The SLN identification rate in the adjuvant and neoadjuvant therapy groups were similar (96.2% vs 95.8%). Mean number of sentinel nodes removed were 2,2 (range 1-15) in the adjuvant group and 2.2 (range 1-7) in the neoadjuvant group. The SLN was positive in the adjuvant group in 151 patients (30%) while in 27 patients (37.5%) in the neoadjuvant group. The SLN was the only positive node in 106 patients (70.1%) in the adjuvant group and in 6(26%) in the neoadjuvant group. Micrometastasis in the SLN was found in 39 patients (7.8%) in the adjuvant group and in 7 (9.8%) patients in the neoadjuvant group. In the adjuvant group, 7 patients (17.9%) had additional non SLN positive in the axillary dissection (ALND), while 3 (49%) in the neoadjuvant group. ALND was performed in all patients with ITC in the SLN in the neoadjuvant setting and 50% of them had additional nonSLN. Discussion. The significance of micrometastasis or ITC in the sentinel node seems to differ in patients with neoadjuvant therapy or surgery first. Micrometastsis or ITC in patients with prior neoadjuvant therapy may reflect residual disease in the axilla, as 50% of patients will have additional positive nodes. Completion axillary node dissection should be considered in this group of patients. Even more, the majority of patients with a positive SLN in the neoadjuvant group harbored additional positive axillary nodes. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-05.